III nitride semiconductors formed from compounds in which N is combined with Al, Ga, In, and the like have conventionally been used as materials for ultraviolet light-emitting devices. III nitride semiconductors made of high-Al-content AlGaN are particularly used for ultraviolet light-emitting devices or deep ultraviolet light light-emitting devices (DUV-LED) emitting light at a wavelength of 300 nm or less.
Examples of the characteristics required of a light-emitting device include high external quantum efficiency properties and low resistance properties. JP 2010-205767 A (PTL 1) describes that a layer serving as an energy barrier for electrons that is called an electron blocking layer is formed between a light emitting layer having a quantum well structure and a p-cladding layer, thereby increasing the light emission efficiency.